AdCP — Sandbox mode

Overview

Sandbox mode lets buyers test the full media buying lifecycle — discovery, campaign creation, creatives, and delivery — without real platform calls or spending real money. Responses contain simulated but realistic data. Sandbox is account-level, not per-request. Once a request references a sandbox account, the entire request is treated as sandbox. This eliminates the risk of accidentally mixing real and test traffic in a multi-step flow.

Capabilities discovery

Sellers declare sandbox support in get_adcp_capabilities:

{
  "account": {
    "sandbox": true
  }
}

Check this before using sandbox mode. If account.sandbox is not declared or is false, the seller does not support sandbox.

Two paths to sandbox

How you enter sandbox mode depends on the seller’s account model (require_operator_auth). The two paths are completely different — make sure you follow the right one.

Implicit accounts (`require_operator_auth: false`)

The seller trusts the agent and does not require per-operator authentication. Sandbox is part of the natural key — the same brand/operator pair can have both a production and a sandbox account, distinguished by sandbox: true. Setup: Declare a sandbox account via sync_accounts with sandbox: true on the account entry:

// sync_accounts — declare a sandbox account
{
  "accounts": [{
    "brand": { "domain": "acme-corp.com" },
    "operator": "acme-corp.com",
    "billing": "operator",
    "sandbox": true
  }]
}

Usage: Reference the sandbox account by natural key with sandbox: true on every request:

// get_products — implicit sandbox
{
  "account": {
    "brand": { "domain": "acme-corp.com" },
    "operator": "acme-corp.com",
    "sandbox": true
  },
  "brief": "Premium CTV inventory for Q2 campaign"
}

Explicit accounts (`require_operator_auth: true`)

The seller requires each operator to authenticate directly. Sandbox accounts are pre-existing test accounts on the seller’s platform — think Stripe test mode, Google Ads sandbox accounts, or Snap test advertiser accounts. You do not create them; you discover them. Setup: Discover sandbox accounts via list_accounts with the sandbox: true filter:

// list_accounts — find sandbox accounts
{
  "sandbox": true
}

The seller returns pre-existing test accounts:

{
  "accounts": [{
    "account_id": "acct_sandbox_acme_001",
    "name": "Acme Test Account",
    "status": "active",
    "sandbox": true
  }]
}

Usage: Reference the sandbox account by account_id on every request:

// get_products — explicit sandbox
{
  "account": { "account_id": "acct_sandbox_acme_001" },
  "brief": "Premium CTV inventory for Q2 campaign"
}

Quick reference

	Implicit (`require_operator_auth: false`)	Explicit (`require_operator_auth: true`)
Sandbox accounts	Declared by buyer via `sync_accounts`	Pre-existing on seller’s platform
Discovery	N/A — buyer creates them	`list_accounts` with `sandbox: true`
Account reference	Natural key with `sandbox: true`	`account_id`
Real-world analogy	Self-service test mode	Stripe test mode, Google Ads sandbox

Response confirmation

Success responses include sandbox: true to confirm the request was processed in sandbox mode:

{
  "products": [...],
  "sandbox": true
}

Full lifecycle example (implicit account)

This example shows the implicit account path. For explicit accounts, replace the natural key account reference with { "account_id": "acct_sandbox_acme_001" } in each step.

1. Discover products

// get_products
{
  "account": {
    "brand": { "domain": "acme-corp.com" },
    "operator": "acme-corp.com",
    "sandbox": true
  },
  "brief": "CTV inventory for brand awareness"
}

2. Create a media buy

// create_media_buy
{
  "buyer_ref": "sandbox_test_001",
  "account": {
    "brand": { "domain": "acme-corp.com" },
    "operator": "acme-corp.com",
    "sandbox": true
  },
  "proposal_id": "prop_abc",
  "total_budget": { "amount": 50000, "currency": "USD" },
  "brand": { "domain": "acme-corp.com" },
  "start_time": { "start_type": "asap" },
  "end_time": "2026-04-01T00:00:00Z"
}

The seller returns a simulated media buy with realistic IDs, packages, and creative deadlines — nothing is booked on any real platform.

3. Upload creatives

// sync_creatives
{
  "account": {
    "brand": { "domain": "acme-corp.com" },
    "operator": "acme-corp.com",
    "sandbox": true
  },
  "creatives": [{
    "creative_id": "hero_video_30s",
    "name": "Brand Hero Video 30s",
    "format_id": {
      "agent_url": "https://creative.adcontextprotocol.org",
      "id": "video_standard_30s"
    },
    "assets": {
      "video": {
        "url": "https://cdn.example.com/hero.mp4",
        "width": 1920,
        "height": 1080,
        "duration_ms": 30000
      }
    }
  }],
  "assignments": {
    "hero_video_30s": ["pkg_001"]
  }
}

4. Check delivery

// get_media_buy_delivery
{
  "account": {
    "brand": { "domain": "acme-corp.com" },
    "operator": "acme-corp.com",
    "sandbox": true
  },
  "media_buy_ids": ["mb_sandbox_123"]
}

The seller returns simulated delivery metrics — impressions, spend, pacing — as if the campaign were running.

Sandbox vs dry run

Some tasks (e.g., sync_creatives) also support a dry_run parameter. These serve different purposes:

	Sandbox account	`dry_run`
Meaning	Nothing is real	Preview changes without applying
Scope	All tasks	sync_creatives only
Side effects	None (simulated)	None (preview only)
Use case	Test the full lifecycle	Check what a sync would change

Seller implementation

When a request references a sandbox account (either via sandbox: true in the natural key or via a sandbox account_id):

Do not make real ad platform API calls (no real orders, line items, etc.)
Do not charge real money or create real billing records
Do validate inputs the same way as production (reject invalid budgets, bad dates, etc.)
Do return realistic response shapes with simulated data
Should include sandbox: true in success responses

Sandbox errors are real validation errors. If a buyer sends an invalid budget using a sandbox account, return a real error — don’t simulate fake errors. For explicit account sellers: ensure your platform has pre-existing sandbox/test accounts that list_accounts can return when filtered with sandbox: true. For implicit account sellers: accept sandbox: true as part of the natural key in sync_accounts and account references. Treat (brand, operator, sandbox: true) as a distinct account from (brand, operator).

Protocol compliance

Sellers that declare account.sandbox: true in capabilities MUST:

Accept sandbox accounts appropriate to their account model
Apply sandbox semantics to all requests referencing a sandbox account
Apply normal input validation (sandbox does not bypass validation)

Sellers SHOULD include sandbox: true in success responses when processing a sandbox account request.

Getting Started

Building with AdCP

Protocol

FAQ

Trust & Security

Reference

Certification

Sandbox mode

Overview

Capabilities discovery

Two paths to sandbox

Implicit accounts (`require_operator_auth: false`)

Explicit accounts (`require_operator_auth: true`)

Quick reference

Response confirmation

Full lifecycle example (implicit account)

1. Discover products

2. Create a media buy

3. Upload creatives

4. Check delivery

Sandbox vs dry run

Seller implementation

Protocol compliance

​Overview

​Capabilities discovery

​Two paths to sandbox

​Implicit accounts (require_operator_auth: false)

​Explicit accounts (require_operator_auth: true)

​Quick reference

​Response confirmation

​Full lifecycle example (implicit account)

​1. Discover products

​2. Create a media buy

​3. Upload creatives

​4. Check delivery

​Sandbox vs dry run

​Seller implementation

​Protocol compliance

Overview

Capabilities discovery

Two paths to sandbox

Implicit accounts (`require_operator_auth: false`)

Explicit accounts (`require_operator_auth: true`)

Quick reference

Response confirmation

Full lifecycle example (implicit account)

1. Discover products

2. Create a media buy

3. Upload creatives

4. Check delivery

Sandbox vs dry run

Seller implementation

Protocol compliance